Damien was able to sense Valentina's soul since she wasn't too far. So he could guess where she sneaked into and why.
Valentina avoided his gaze and looked down as if she did something wrong. She realized that Damien found out about her quick little visit and didn't know if he was going to be angry at her or how he was going to react.
The only thing that relieved her was that she could sense his soul was very calm without any turbulent emotions, which could also mean that he was suppressing his emotions.
But she had no idea that Damien was really feeling calm, and in fact, he was feeling happier and only put up a serious expression to simply tease Valentina.
He knew how much she loved him to death and that she would think twice before she does anything that could hurt him as well, even if she was still trying to keep her feral instincts in control.
